package com.hmdp.utils;

import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.stereotype.Component;

import javax.annotation.Resource;
import java.time.LocalDateTime;
import java.time.ZoneOffset;
import java.time.format.DateTimeFormatter;

/**
 * @author jay
 * 全局ID生成器
 */
@Component
public class RedisIdWorker {

    /**
     * 开始时间戳，2023
     */
    private static final long BEGIN_TIMESTAMP = 1672531200L;
    /**
     * 序列号位数
     */
    private static final int COUNT_BITS = 32;
    @Resource
    private StringRedisTemplate stringRedisTemplate;

    public long nextId(String keyPrefix){
        // 生成时间戳
        LocalDateTime now = LocalDateTime.now();
        long nowSecond = now.toEpochSecond(ZoneOffset.UTC);
        long timestamp = nowSecond - BEGIN_TIMESTAMP;
        // 生成序列号
        // 获取当前日期，年月日
        String date = now.format(DateTimeFormatter.ofPattern("yyyy:MM:dd"));
        long count = stringRedisTemplate.opsForValue().
                increment("icr:" + keyPrefix + ":" + date);

        // 拼接并返回，位运算
        return timestamp << COUNT_BITS | count;
    }
}
